Our invention relates to an apparatus for data transfer with a flexible magnetic disk commonly known as a floppy disk, and more specifically to such an apparatus, or a disk drive as the apparatus is sometimes referred to, having a transducer head constructed and arranged for the ready establishment of proper data transfer contact with the flexible magnetic disk.
The flexible magnetic disk is now unquestionably one of the most widely accepted information storage media. There have been suggested and used various types of such disks, as well as of matching disk drives, as disclosed for example in Dalziel et al. U.S. Pat. No. 3,678,481 and Takahashi et al. U.S. Pat. No. 4,445,155. The magnetic disks in current use may be broadly classified as single or double sided, depending upon whether information is stored on one or both surfaces of the disk. A disk drive for use with a single sided magnetic disk has, of course, but one magnetic transducer head for data transfer with one surface of the disk, and a pressure pad which is sprung against the other surfaces of the disk. The transducer head has a curved or rounded contact surface, for data transfer contact with the magnetic disk, having defined therein a transducing gap such as a read/write gap, perhaps together with a pair of erase transducing gaps for erasing the opposite marginal edges of a track of information on the magnetic disk for an improved track density.
Heretofore, in this type of transducer head, the read/write transducing gap has been so positioned on its contract surface as to be on a notional line passing the apex of the rounded contact surface and extending normal to the radial direction of the magnetic disk, with a view to a minimum spacing loss between the transducing gap and the disk. The spacing loss will indeed be reduced to a minimum if the transducer head is so mounted that its transducing gap is positioned on that line. In practice, however, rarely has the transducing gap been placed exactly on the line by reasons of unavoidable dimensional or mounting errors.
A conventional solution to this problem has been to employ a magnetic disk having prerecorded thereon a signal for the head alignment purpose. The head alignment signal is read out following the assemblage of the disk drive, and the angular position of the transducer head is readjusted so that the signal output may become maximum or attain some other prescribed level. We object to this solution because of the lengthy and troublesome procedure involved for the fine readjustment of the head position with respect to the magnetic disk, leading to an increase in the manufacturing cost of the disk drive.